Open AccessSex‐biased initial eggs favours sons in the slightly size‐dimorphic Scops owl ( Otus scops )
Author(s) -
BLANCO G.,
DÁVILA J. A.,
SEPTIEM J. A. LÓPEZ,
RODRÍGUEZ R.,
MARTÍNEZ R.
Publication year - 2002
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2002.tb01709.x
Subject(s) - biology , hatching , fledge , sexual dimorphism , zoology , population , sex ratio , offspring , ecology , demography , pregnancy , genetics , sociology
We assessed the potential control of female Scops owls ( Otus scops ) over the production of daughters and sons in relation to their order in the laying sequence, and investigated the possible adaptive value of such control on the survival and growth of nestlings. The population sex ratio at fledging was not significantly biased. A relationship between ovulation order and egg sex was found, which was mostly due to the strong male biased sex ratio among initial eggs, as 17 of 18 first‐hatched chicks (94%) from first‐laid eggs were males. Asynchronous laying and subsequent asynchronous hatching resulted in a decreasing survival of chicks with increasing hatching order. Female chicks fledged with a higher mass than males and fledging mass decreased with hatching order due to male biased hatching order and its influence in the growth of the single first‐hatched female. These results suggest that female Scops owls may be able to adjust the sex of their offspring at egg production to invest differentially in their survival and growth. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 76 , 1–7.